One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,7)(3,6,4,8)(9,10,13,16)(11,17,19,14)(12,20,21,15)(18,22,24,23)(25,26,31,28)(27,32,38,39)(29,33,30,34)(35,37,40,36)(1,3,5,4)(2,6,7,8)(9,11)(10,14)(12,18)(13,19)(15,22)(16,17)(20,23)(21,24)(25,27,31,38)(26,32,28,39)(29,36,30,37)(33,35,34,40)(2,7)(6,8)(25,28,31,26)(27,35,38,40)(29,33,30,34)(32,37,39,36)(9,12,13,21)(10,15,16,20)(11,18,19,24)(14,22,17,23)(25,29,31,30)(26,33,28,34)(27,36,38,37)(32,35,39,40)(1,4,5,3)(2,8,7,6)(11,19)(14,17)(18,24)(22,23)(27,37)(29,30)(32,40)(33,34)(35,39)(36,38)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.